generic_file_read_iter(): make use of iov_iter_revert()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2017-04-13 14:13:36 -04:00
parent 639a93a521
commit 5ecda13711

View File

@ -2033,7 +2033,6 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
if (iocb->ki_flags & IOCB_DIRECT) {
struct address_space *mapping = file->f_mapping;
struct inode *inode = mapping->host;
struct iov_iter data = *iter;
loff_t size;
size = i_size_read(inode);
@ -2044,11 +2043,12 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
file_accessed(file);
retval = mapping->a_ops->direct_IO(iocb, &data);
retval = mapping->a_ops->direct_IO(iocb, iter);
if (retval >= 0) {
iocb->ki_pos += retval;
iov_iter_advance(iter, retval);
count -= retval;
}
iov_iter_revert(iter, iov_iter_count(iter) - count);
/*
* Btrfs can have a short DIO read if we encounter
@ -2059,7 +2059,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
* the rest of the read. Buffered reads will not work for
* DAX files, so don't bother trying.
*/
if (retval < 0 || !iov_iter_count(iter) || iocb->ki_pos >= size ||
if (retval < 0 || !count || iocb->ki_pos >= size ||
IS_DAX(inode))
goto out;
}